The present invention relates to a radio communication apparatus which performs a communication by selecting a radio channel to be used from a plurality of channel groups.
A conventional radio communication apparatus measures the carrier levels of a plurality of radio channels available, determines channels whose carrier levels are equal to or lower than a given reference value as idle channels, and selects an arbitrary one of the idle channels to perform a communication.
When a plurality of such radio communication apparatuses are used within an identical radio area, if a plurality of channels are simultaneously used, as shown in FIG. 2, intermodulation waves are generated. For this reason, if an idle channel is merely selected and used, the intermodulation may adversely influence channels in use. In order to eliminate the adverse influence due to the intermodulation, a channel in use which may cause intermodulation with other channels is calculated and stored as an invalid channel, and is excluded from channel candidates to be selected.
However, when a plurality of radio communication apparatuses are used within a single radio area, all the combinations of channels in use may cause intermodulation, and the number of intermodulation waves becomes huge.
Under such conditions, in the above mentioned method that takes intermodulation into consideration upon selection of a channel, intermodulation waves may be generated over a broad range depending on the combination of selected channels, and the number of channels that can be used may become extremely small.